Hollow core or block for use in concrete structures



Dec. 27, 1932.- A. s. MACDONALD 1,892,311

HOLLOW CORE OR BLOCK FOR USE IN CONCRETE STRUCTURES Filed Jan. 12, 1931 3 Sheets-Sheet 1 Dec. 27, 1932. A. s. MACDONALD 1,892,311

HOLLOW CORE OR BLOCK FOR USE IN CONCRETE STRUCTURES Filed Jan. 12, 1931 3 Sheets-Sheet 2 I'm/en for. file/ta na er .f/k/p an Macdo naJd,

e WWAW Dec. 27, 1932. A. s. MACZDONALD 1,892,311

HOLLOW CORE OR BLOCK FOR USE IN CONCRETE STRUCTURES Filed Jan. 12. 1931 3 Sheets-Sheet 3 45' ll 45 7 II FIG-l0 jm/enzorr #Zera/za er 3 /17 0107: l/acda nab! Patented Dec. 27, 1932 UNITED STATES PATENT OFFICE HOLLOW CORE OR BLOCK FOR USE IN CONCRETE STRUCTURES Application filed January 12, 1931, Serial No. 508,204, and in Australia May 26, 1930.

This invention relates to improvements in hollow cores, domes, or blocks for use in the formation of concrete structures and has particular reference to the formation of concrete floors and the like.

An object of the invention is to produce a light, cheaply constructed, and if desired easily removable hollow block or the like which, if desired, may be left in position after the concrete has set.

A further object of the invention resides in the provision of internal reinforcing means for the hollow block which are capable of being removed for re-use in forming another block, dome or the like.

According to the present invention the shell of the hollow block, or the like hereinafter referred to as a dome, is preferably made from strawboard, corrugated paper, sheet metal, or other light material such as moulded or compressed paper, henceforth referred to as paper board, and is disposed in box like formati on having four sides which may be closed at the top and/or bottom.

The bottom portion of the dome is preferably left open in order that internal reinforcements may be inserted therein. If desired these may be withdrawn therefrom after the concrete has set.

In cases where the shell of the dome is made from metal, it may be produced from a stamping folded or bent to the desired shape.

The reinforcements for the shell of the block may be of wood or metal but are preferably of cellular formation produced by a plurality of longitudinal and transverse strips of material such as strawboard, corrugated paper, sheet metal or other light material.

The cellular formation may be produced by slitting, or what is known as halving, the strips at right angles to their longitudinal edges and then meshing the transverse strips with the longitudinal strips until their upper edges, and the lower edges respectively are flush and in the same respective plane.

The method of producing the above cellular formation is well known, and is given as an example of one form of internal reinforcement necessary in the present invention.

Two or more of the lower edges of the shell of the block may be provided with flaps, lugs or the like whereby the shell of the block, owing to its light nature may be held in position during the act of pouring the concrete.

But in order that the invention may be more readily understood reference will now be made to the accompanying drawings wherein Figure 1 is an isometric view illustrating the present invention in the form of a paper board shell, portion being broken away to show a collapsible cellular core used therewith.

Figure 2 is an isometric View of one form of collapsible paper board core disposed in cellular formation and produced from sheets of paper board slit at intervals and interconnected by what are known as halved joints.

Fig. 3 is an elevational view of one of the vention and in which the sides are formed.

with gaps at the corners.

Figure 6 is an isometric view of a collapsible wood core also adapted for usewith a pa per board cover of the kind illustrated in Figure 1.

Figure 7 illustrates in sectional elevation a cellular dome according to Figures 1, 2 and 3, used in a floor system construction with a ceiling having metal lathnig as a base for the plaster.

Figure 8 illustrates a similar view of a'cellular dome used in a floor system with timber battens, and applied fibrous plaster ceilings, the dome being reinforced by a removable core of the kind shown in Figure 2.

Figure 9 shows the application of a paper board core of the kind illustrated in Figure 1, to standard adjustable wood cores, the core being removable.

Figure 10 is a part sectional elevation illustrating the manner in which several domes are placed end to end to form a trough like girder and also illustrates the overlapping of the ends of the shell to form a cover strip over the gap between two adjacent domes.

The dome shell 11 illustrated in Figure 1, is formed from corrugated paper, strawboard, sheet metal or other light material; for the purpose of this specification termed paper board. The said shell 11 is formed by folding or pressing the paper board into the substantially rectangular body, having four sides 12 of equal length which terminate in flanges 13. The sides, however, may not be all of the same length provided that a rectangular body is produced.

Each shell 11 is provided with a core of which several kinds may be used. The cellular core illustrated in Figure 2 has been found very suitable. This is formed from strips 14 of paperboard or the like, slit or cut as shown in Figure 3. The core however, may be of wood as shown in Figures 4 or 6, or of metal as shown in Figure and may also be formed integral with the shell, from the material thereof.

The collapsible cellular core illustrated in Figure 2 is formed from strips 14, Figure 3, of material such as paper board, having slots 15 formed therein at intervals. The slots 15 are of slightly greater width then the thickness of the material and extend transversely of the respective strip 14 for slightly more than half the Width thereof. As illustrated in Figure 2, six strips 14 are shown interconnected to form a number of cells 16 in well known manner. The cellular core Figure 2, is placed in the dome shell 11. and gives rigidity thereto when the concrete is being poured.

The cellular cores, Figures 2 and 3, and the shells 11 are waterproofed especially at the lower edges. For this purpose parafiin wax, animal fat, nitro cellulose paint, may be used.

The wooden core illustrated in Figure 4. has a top 17 and four tapered s des 18; and is of ordinary well known construction.

In cases where the core is formed from sheet metal the material from which it is made is bent or folded to form a top 19 and four sides 20, two of which appear in Figure 5. The sides of the core are made to produce a gap 21 at the corners in order that the sides may be sprung inwards when it is desired to remove the core from the shell. The sides are perforated near the corners in the usual manner.

The wooden core shown in Figure 6 has four sides 22, 23, 24,25 and a loosely applied top 26, the sides being loosely connected by means of stops 27, 28 and suitable brackets 29.

Figure 7 shows the dome shell 11 in position upon metal lathing 30 which acts as a base for plaster 31. In this case, a cellular core having strips 14 of the kind illustrated in Figure 2 is used, the shell 11 and core being left in position after the concrete 32 for the floor has been poured and set.

Figure 8 illustrates the application of a shell 11 and cellular core, Figure 2, to a floor system wherein timber battens 33 are secured to the concrete 34 by hooked nails 35, the battens 36 being provided for affixing a fibrous plaster ceiling 37 in position. With this application of the invention the core and shell 11 may be removed if desired. Other applications of the invention will occur to persons versed in the art.

When it is desired to use a standard adjustable wooden core of the kind illustrated in Figures 4 or 6 as a reinforcment for the shell 11 in a floor system as shown in Figure 9, the usual posts 40, joists 41, cleats 42, separators 43, and sole plate 44, are provided to form the timbering for the work. The shells 11 are placed over the cores and are secured at their flanges 13 to the sole plates 44 by clout tacks 38.

After the concrete 47 has set, the core can be easily removed owing to its tapered nature and the fact that the paper board shell 11 preserves a substantially smooth flat surface where it contacts with the core. Irregularities in the core surface are not therefore reproduced in the concrete 47 to cause an i obstruction or resistance to withdrawal of the core.

In practice the usual supports and forms are placed in position and the domes 11 with their cores are then assembled in the desired order and secured by the tacks 38, which are passed through the flanges '13 of the shells 11. The concrete is then poured in the usual manner: and after it has set for the required period, part of the timbering is removed, and I if desired, the dome shell 11 and the core reinforcements also are removed. Finally the joists 43 and the remaining portion of the timbering are removed. Alternatively the shell may be left in position, and only the core removed, in which case it may be used again with another shell.

lVhere a longitudinal trough like girder is to be produced the domes are placed side by I side in a row as in Figure 10 and the side or sides 12 of the shell 11 is or are overlapped across the gap 39 to form a cover joint. Instead of using the side or sides 12 as a cover for the gap 39 between the shells 11, I may provide strips of rigid material for that purpose.

I claim:

A hollow dome for use in the formation of concrete structures comprising a shell of box-like formation, and a core formed from a. single sheet of material adapted to be fitted in the dome and including a top and four sides, said sides having their adjacent ends spaced to provide gaps, said sides being flexibly connected with the top whereby they may be moved inwardly to close the gaps to faeilitate the withdrawal of the core from the dome.

In testimony whereof I have hereunto set my hand.

ALEXANDER SIMPSON MACDONALD. 

